MXPA00004537A

MXPA00004537A - Flashover protection cover for electrical power lines.

Info

Publication number: MXPA00004537A
Application number: MXPA00004537A
Authority: MX
Inventors: George W Kayser
Original assignee: Tyco Electronics Corp
Priority date: 1997-12-10
Filing date: 1998-12-08
Publication date: 2002-04-24
Also published as: IL135975A; KR20010052098A; CA2309429C; IL167964A; DE69841675D1; CA2309429A1; EP1038345A1; JP4823416B2; CN1281593A; KR100596951B1; ES2348497T3; BR9812781B1; US6239357B1; PT1038345E; ATE468644T1; NZ504297A; BR9812781A; WO1999030399A1; AU754842B2; CN1175538C

Abstract

Flashover protection covers are provided in a continuous length for covering power line spans between supporting structures. A flexible panel includes an inner surface and generally parallel opposite edge portions configured to be joined together to form a first longitudinally extending chamber. A longitudinally extending first wall is connected along an edge portion thereof to the inner surface of the panel. The first wall has an opposite free edge portion and is configured to form a second longitudinally extending chamber within the first chamber. The second longitudinally extending chamber is configured to enclose a power line when the panel edge portions are joined together. A second wall is connected along an edge portion thereof to the inner surface of the panel and is configured to inhibit electrical arcing from the power line into the first chamber between the first wall free edge portion and the panel inner surface.

Description

CURRENT JUMP PROTECTION COVER FOR ELECTRIC ENERGY LINES Field of the Invention The present invention relates generally to insulating covers, and more particularly, to insulating covers for high energy transmission lines.

BACKGROUND OF THE INVENTION Electrical energy can be transmitted from a generation source to consumers by means of elevated conductors suspended between towers or poles. Electric power is normally transmitted in phases, where multiple conductors are used. One or more of these conductors are "hot" conductors, which carry a specified amount of AC electric power, and a conductor serves as a ground. If the hot conductors or between the hot conductors and other earthed objects are contacted, they may result in power surges. Non-grounded contact with a hot conductor, such as when a bird perches on a hot conductor, usually does not result in a current jump. Because non-insulated conductors are usually less expensive than insulated conductors, many electric power providers use non-insulated conductors for power transmission. Frequently, hundreds of thousands of transmission power lines, and the use of non-insulated conductors, can result in large cost savings for electric power providers. Non-insulated conductors are usually hung between towers or poles, in such a way that there is sufficient tolerance between the conductors, to avoid contact between conductors or with objects to ground. Although bare conductors may be less expensive to install than insulated conductors, potentially costly problems can arise as a result of their use. Adequate tolerances between conductors and / or other objects to ground may not be susable during adverse weather conditions (ie, storms and high winds). As a result, the potential for current jumps caused by conductors making contact with each other or with another object can be increased. Another source of current leaks may be caused by large birds and animals that are large enough to make contact with a hot conductor and a grounded object or other conductor. In addition, falling trees and tree branches can cause contact between hot conductors and earth, resulting in power surges. Current jumps can result in energy depletion, which is undesirable for electric power providers and consumers. For existing power transmission systems, electric power providers may find it desirable to replace bare conductors with insulated conductors, in order to eliminate the opportunity for power surges. Unfortunately, the cost of replacing bare conductors with insulated conductors can be expensive. In addition, an interruption in the power supply may be required to replace the conductors. This can be economically inconvenient for an electric power supplier, as well as undesirable for electric power consumers. There are insulating covers for temporary use in protecting workers from live power lines. Unfortunately, these insulating covers are usually designed for short-term and / or local use. In addition, existing roofs, such as the Overhead Line Insulating Cover, are usually available only in short stretches, typically 10 feet (3 meters) and less. Due to their shape and configuration, these temporary covers can be bulky and a bit difficult to handle in longer stretches. A section of an energy line between the support towers or poles may exceed hundreds of meters. As a result, many of these temporary covers may be required to cover an entire stretch. Unfortunately, the gaps between the adjacent decks would be potential sources of current leaks.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide covers capable of protecting the high energy transmission lines from the current jumps caused by the contact with a. object to ground or another conductor. It is another object of the present invention to provide surge protection covers that can be installed in existing power transmission lines without requiring a lack of power during installation. It is still another object of the present invention to provide current protection covers in a continuous configuration, to cover an entire length of power transmission line between the support structures. These and other objects of the present invention are provided by current surge protection covers; provided in continuous sections that can enclose a live electric power line inside a chamber contained inside another chamber. A flexible panel has an internal surface and generally parallel opposite edge portions configured to be joined together, to form a first longitudinally extending chamber. A first longitudinally extending wall has an arcuate shape connected along a portion of the edge thereof with the inner surface of the panel. The first wall also has a free opposite shore portion. The first wall is configured to form a second chamber that extends longitudinally inside the first chamber. The second longitudinally extending chamber is configured to enclose a power line when the panel edge portions are joined together. The free edge portion of the first wall may abut or may be in close proximity to the inner surface of the panel when the edge portions of the panel are joined together. A second wall is connected along a portion of the edge thereof, with the inner surface of the panel, and includes an opposite free edge portion. The second wall is configured to be longitudinally coextensive with the first chamber. The edge portion of the second wall is connected to the inner surface of the panel in a spaced apart relationship generally parallel to the edge portion of the first wall, such that the second wall is adjacent to the free edge portion of the first wall. wall when the edge portions of the panel are joined together. The second wall inhibits the electric arc of the energy line to the first chamber between the free edge portion of the first wall and the inner surface of the panel. The second wall also increases the leakage length of the current surge protection cover. The current surge protection covers according to the present invention can be provided in continuous sections sufficient to cover the stretches of the power lines of any length. A plurality of slots are formed in the first and second wall of the cover, to facilitate the winding or winding of the cover not installed around a spool or similar device. A live electrical power line is placed between the first arched wall and the inner surface of the panel. Then, the edge portions of the panel are secured together to enclose the energy line inside the longitudinally extending chamber defined therein. The plurality of grooves that facilitate the provision of the cover in a generally flat non-installed configuration are covered during installation with electrically insulating material, before securing the edge portions of the panel to each other. When the edge portions of the panel are secured together, the cover can be advanced along the length of the power line. Alternatively, a current surge protection cover can be applied, according to the present invention, to a live energy line continuously. The installation operations are preferably carried out by means of a remotely controlled device that is stationary or movable along a length of power line. The current surge protection covers according to the present invention are convenient, because they can be installed in existing power transmission lines without requiring the power lines of the service to be removed. The covers according to the present invention provide sufficient electrical insulation to prevent the power line current jump if adjacent power lines are touched, such as during high winds, or if an object to ground contacts, such as a tree or an animal, with an energy line. By reducing the potential of current jumps, the possibility of energy faults is reduced. In addition, the risks associated with power surges, such as fires, are also reduced.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates an energy gap protection cover not installed for a high energy transmission line, in accordance with the aspects of the present invention. Figure 2 is a cross-sectional view of the current surge protection cover of Figure 1 in an installed configuration, enclosing an energy transmission line. Figure 3 illustrates grooves formed in the wall portions of the current surge protector cover of Figure 1, which allow the cover, in its non-installed configuration, to wrap around a spool. Figure 4 illustrates the current surge protection cover of Figure 1, wrapped around a spool. Figure 5 illustrates the insulating material covering the grooves in the wall portions of a current surge protection cover. Figure 6 illustrates the enclosing of an entire length of power transmission line with a current surge protection cover in accordance with the present invention. Figure 7 is a flow diagram schematically illustrating the operations for enclosing an energy transmission line with a current surge protector cover according to the present invention. Figure 8 is a cross-sectional view of the current surge protection cover according to another embodiment, in an installed configuration, enclosing an energy transmission line. Figures 9A-9B illustrate a current surge protection cover not installed for a high energy transmission line, in accordance with another embodiment of the present invention. Figure 9C is a cross-sectional view of the current surge protector cover of Figures 9A-9B in an installed configuration. Figure 10 is a cross-sectional view of the current surge protection cover according to another embodiment.

Detailed Description of the Invention The present invention will now be described more fully hereinafter, with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. However, this invention can be incorporated in many different forms, and should not be construed as limited to the modalities stipulated herein; rather, these embodiments are provided in such a way that this disclosure is absolute and complete, and that it fully transmits the scope of the invention to those skilled in the art. Equal numbers refer to the same elements throughout the description. Referring now to Figures 1 and 2, a current surge protection cover 10 is illustrated to cover a high energy transmission line, in accordance with aspects of the present invention, in a non-installed configuration (Figure 1) , and in an installed configuration (Figure 2). The cover 10 includes a flexible continuous panel 12 having an internal surface 12a, and generally parallel opposed edge portions 14a and 14b. The opposite edge portions 14a, 14b are configured to be joined together, in order to form a first longitudinally extending chamber 16 (Figure 2). In the illustrated embodiment, the edge portion 14b is configured to removably receive the edge portion 14a therein. The edge portion 14a has an "arrowhead" configuration with shoulder portions 15 configured to be retained by the resilient members 17 of the edge portion 14b. The illustrated embodiment provides elements to maintain the edge portions of panel 14a, 14b joined together under adverse conditions, while allowing the cover to be removed, if necessary, at a later time. The present invention is not limited to the illustrated embodiment. Alternative locking mechanisms that have different shapes can be used, including, but not limited to, locking devices in the form of "L", "C", or "Z". Alternatively, "hook and loop" fasteners, such as VelcroR (Velero USA, Inc., Manchester, NH) fasteners, can be used to hold the edge portions of panel 14a, 14b together. Preferably, a sealing material is applied to the environment between the elastic members 17 of the edge portion 14b. A preferred material is a low modulus elastomer, as described in the pending application, commonly assigned to Chang, serial number 08 / 876,270, filed on June 16, 1997, the disclosure of which is incorporated into the present as a reference. A first longitudinally extending wall 18 is connected along a first edge portion 18a thereof with the inner surface of the panel 12a, as illustrated. The first wall 18 has a free edge portion 18b that is generally parallel with the first edge portion 18a. Preferably, the first wall 18 has an arcuate shape. As illustrated in Figure 2, the first wall 18 is configured to form a second longitudinally extending chamber 20 inside the first chamber 16. The second longitudinally extending chamber 20 is configured to enclose an energy line 22 when they join together the edge portions of panel 14a, 14b. As illustrated in Figure 2, the free edge portion 18b of the first wall is slightly separated from the inner surface of the panel 12a when the edge portions of the panel 14a, 14b are joined together. Preferably, the free edge portion of the first wall 18b is separated from the inner surface of the panel 12a by between about 1 and 2 millimeters (mm). The first wall can also be configured in such a way that its free edge portion 18b abuts the inner surface of the panel 12a without any gap between them, or with as little space as possible. The first wall 18 is not limited to the illustrated configuration. The first wall 18 may have a non-arched shape, or may have an arched shape different from that illustrated, without departing from the spirit and intent of the present invention. Still referring to Figures 1 and 2, a second wall 24 is connected along a first edge portion 24a thereof, with the inner surface of the panel 12a, as illustrated. The second wall 24 is preferably configured to be longitudinally coextensive with the first chamber 16 when the edge portions of the panel 14a, 14b are joined together. The second wall 24 has a free edge portion 24b that is generally parallel with the first edge portion 24a. The second wall 24 and the first wall 18 are connected to the inner surface of the panel 12a in a separate, generally parallel relationship. The second wall 24 is preferably placed adjacent the free edge portion of the first wall 18b when the edge portions of the panel 14a, 14b are joined together. This configuration inhibits the propagation of the electric current jump or arcing from the energy line 22 into the first chamber 16 between the free edge portion of the first wall 18b and the inner surface of the panel 12a. This may result, for example, if an earthed object comes into contact with the cover 10 near the edge portions 14a, 14b. There may be a high voltage between the conductor and the ground object, which may result in the current jump from the power line 22 to the object to ground between the free edge portion of the first wall 18b and the inner surface of the panel 12a. The present invention is not limited to the illustrated embodiment. Additional walls can be used to control the potential arc formation and the current jump from a power line 22 enclosed inside the second chamber 20. In addition, the cover 10 may have other non-circular cross-sectional configurations. For example, an alternative embodiment of a current surge protection cover 50 is illustrated in FIG. 8, where a single wall 24 is used. The wall 24 may extend substantially through the diameter of the cover 50. Additionally, the embodiments illustrated in Figures 2, 8, 9C, and 10, may include an additional member overlapping a gap between a free edge portion of the wall and the inner surface of the cover. For example, in Figure 2, an additional member, not shown, can extend from the inner surface of the panel 12a, and can be superimposed on the illustrated gap between the free edge portion of the second wall 24b and the inner surface of the second wall 24b. panel 12a. The additional member provides protection against arcing through the gap. The additional member can have virtually any shape; however, a "U" or "V" shape may be preferred. Referring now to Figures 3 and 4, a current surge protector cover, in accordance with the present invention, may include a plurality of slots 30 formed in the first and second walls 18, 24. These slots 30 allow the flexible panel 10, with the first and second walls 18, 24 connected thereto, are wound around a spool or other device. Without the slots 30, it can become difficult to wind any significant length of the panel around a spool without damaging the panel. Preferably, the slots of the first and second walls 18, 24 are formed therein in separate sections, as shown in FIG. illustrated in Figure 4. Because the arc can travel from an energy line enclosed within the second chamber 20 through a slot 30, it is desirable to reduce the number of slots 30 required to effectively roll the cover 10 around a reel. In the illustrated embodiment of Figure 4, the slots 30 are formed in the first wall 18 of the cover 10 in repetitive increments w '' that facilitate the wrapping of the cover around an elliptical spool. The grooves formed in the first wall 18 can be offset from the grooves in the second wall 24 to inhibit the formation of an arc towards the first chamber 16. Different patterns of groove repetition can be used, in such a way that the cover 10 can roll around different shapes and sizes of reels or other storage devices, while reducing the number of slots 30, without departing from the spirit 10 and intention of the present invention. Preferably, the slots 30 are covered after the cover of a reel is unwound, either before, or during, the installation around an energy transmission line. As illustrated in Figure 5, it can be applied 15 a layer of insulating material 32 over the slots 30. The insulating material inhibits the passage of the electric arc through the slots 30. In addition, the slots 30 may have an adhesive or other insulating material placed therein. The flexible panel 12 and the first and second walls 20 18, 24 are preferably formed of a polymeric material of high dielectric strength, including, but not limited to, medium or high density polyethylene. In addition, it is preferred that the material from which the flexible panel 12 and the first and second walls 18, 24 are formed has a 25 good protection from ultraviolet radiation (UV), have a good resistance to the formation of tracks, to erosion, and to abrasion. As is known to those skilled in the art, "track formation" is a permanent damage to the insulating material that leaves a carbonized conductive path that deteriorates the insulating properties of the material. It is also preferred that the material from which the flexible panel 12 and the first and second walls 18, 24 are formed have a minimum life of 20 years in an environment at 90 ° C. Referring now to Figures 6 and 7, the operations to apply a current surge protection cover, in accordance with the present invention, to an energy transmission line are illustrated. The current surge protection cover 10 is provided in a continuous tremor, preferably wound around a spool 40, or other supply element. The material 32 for covering the portions of the cover having grooves therein, is preferably provided by means of a spool 42, or other supply element. A remotely controlled installation reel 44 applies the insulating material 32 over the slots, and encloses the cover 10 around the power line 22, as described above. The installation spool moves continuously along the length of the power line 22, performing the installation operations. In an alternative way, the installation reel 44 can be stationary, and the installed cover is advanced along the length of the power line. The installation reel serves as a means to perform the functions of inserting a live electricei power line between the first arched wall and the inner surface of the panel. The installation reel also serves as a means for performing the functions of securing the edge portions of the panel 14a, 14b to each other, for enclosing a live electrical power line inside the longitudinally extending chamber 20, and for covering the plurality of slots 30 with electrically insulating material 32 before securing the edge portions of the panel together. The operations described above for installing a current surge protection cover on a live power line are illustrated schematically in Figure 7. A continuous section of current protection cover is provided to an installation reel (block 100). ). A live energy line 22 is inserted between the first wall 18 and the inner surface of the panel 12a (block 110). The slots 30 inside the portions of the first and second walls are covered with insulating material 32 (block 120). The edge portions of the panel 14a, 14b are secured together to enclose the live energy line inside them. (block 130). Then the installed cover can be advanced along the length of the power line (Block 140). The installation operations are preferably carried out by means of a remotely controlled installation device, which is stationary or movable along a stretch of power line. When a surge protection cover is dispensed from a reel and onto a conductor, the installation reel will adjust the edge portions of the panel 14a, 14b to each other, and preferably move the cover down the line portion of the panel. Energy. In an alternative way, the installation tool can be configured to "traverse" the stretch of the power line, as it ensures a protection cover of current flows to it. However, the current surge protection covers, according to the present invention, can also be installed manually. The present invention is convenient, because a current surge protection cover can be supplied in a continuous section to cover long stretches of power transmission lines. Preferably, current protection covers according to the present invention can be supplied in any length to cover all the conductor sections. The present invention can be used to cover power transmission lines up to and exceeding 25 millimeters in diameter, and operating up to and exceeding 25,000 volts, without limitation. Referring now to Figures 9A-9C, a current surge protection cover 60 is illustrated for a high energy transmission line, in accordance with another embodiment of the present invention. Figures 9A and 9B illustrate the current hop cover 60 in a non-installed configuration. Figure 9C is a cross-sectional view of the current surge protection cover 60 in an installed configuration. The cover 60 includes a panel 61 having opposite end portions 62a and 62b. A formable member 64 extends from the panel 61 between the end portions 62a, 62b, as illustrated. Member 64 can be configured to obtain an arched shape when; connect end portions 62a and 62b, as illustrated in Figure 9C. Alternatively, member 64 may be thermoformable during installation. The illustrated end portions 62a and 62b have an arcuate shape, and are configured to be interlocked, as illustrated in Fig. 9c, to secure the cover 60 around an electrical conductor 22. Fig. 10 is a cross-sectional view of a surge protection cover 70, in accordance with another embodiment of the present invention. The illustrated cover 70 has a "bell" shape, and includes a wall 74 extending through the inner diameter of the cover. The end portions 72a and 72b are configured to engage when the cover 70 is installed around an electrical conductor 22. Alternatively, the portion of the illustrated cover 70, which includes the wall 74 and the end portions 72a and 72b , it can have a reduced diameter, compared to the portion of the cover that immediately surrounds the electrical conductor 22. Although it is preferable that a section of electric power line be covered with a single cover in accordance with the present invention, multiple covers. A connector can be used to join multiple adjacent decks to each other along a stretch. The foregoing is illustrative of the present invention, and should not be construed to limit it. Although a few example embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications to the exemplary embodiments are possible without departing materially from the novel teachings and advantages of this invention. In accordance with the foregoing, it is intended that all such modifications be included within the scope of this invention as defined in the claims. In the claims, the media clauses plus function, are intended to cover the structures described herein that perform the function mentioned, and not only the structural equivalents, but also the equivalent structures. Therefore, it should be understood that the foregoing is illustrative of the present invention, and should not be construed as limited to the specific embodiments disclosed, and that it is intended that modifications to the disclosed embodiments be included, as well as other embodiments, within the scope of the appended claims. The invention is defined by the following claims, the equivalents of the claims being included therein.

Claims

1. A cover of protection of current jumps for a line of electrical energy, which comprises; : a flexible panel having an internal surface, and oite edge portions generally parallel, the edge portions being configured to be joined together to form a first longitudinally extending chamber; and a first longitudinally extending wall connected along a edge portion of the first wall with the inner surface, and having an oite free edge portion, wherein the first wall is longitudinally coextensive with the first chamber that is extends longitudinally, the first wall being configured to form a second chamber extending longitudinally inside the first chamber, when the edge portions of the panel are joined together, wherein the second longitudinally extending chamber is configured to enclose a line of electrical power, and wherein the second longitudinally extending chamber is longitudinally coextensive with the first longitudinally extending chamber.

2. A surge protection cover according to claim 1, which further comprises a second wall connected along a edge portion of the second wall with the inner surface, and having an oite free edge portion, wherein the second wall is longitudinally coextensive with the first longitudinally extending chamber.

3. A cover of protection of jumps of current; according to claim 2, wherein the edge portion of the second wall is connected to the inner surface of the panel in a spaced-apart relationship generally parallel to the edge portion of the first wall, such that the second wall is adjacent to the free edge portion of the first wall, when the edge portions of the panel are joined together, to thereby inhibit the electric arc from the power line to the first chamber between the free edge portion of the first wall and the internal surface of the panel.

4. A current surge protection cover according to claim 1, wherein the first wall has an arcuate shape.

5. A current surge protection cover according to claim 1, wherein the free edge portion of the first wall abuts the inner surface of the panel when they are joined together. - r - ~ - * • • • • "'edge portions of the panel

6. A current surge protection cover according to claim 2, which further comprises a plurality of grooves formed in the first and second walls for to facilitate the winding of the cover in a configuration not installed around a spool

7. A current surge protection cover according to claim 6, which further comprises a layer of insulating material that overlaps the slots. A current surge protection cover according to claim 1, wherein the panel and the first and second walls are formed of high dielectric strength polymer material 9. A surge protection cover according to claim 2, wherein the free edge portion of the first wall abuts the inner surface of the panel, when the edge portions of the panel are joined together. protection of current jumps; according to claim 2, which further comprises a plurality of grooves formed in the first and second walls, to facilitate winding of the cover in a configuration not installed around a spool. 11. A current surge protection cover according to claim 2, wherein the panel and the first and second walls are formed of polymeric material of high dielectric strength. 12. A surge protection cover according to claim 10, which further comprises a layer of insulating material that overlaps the slots. 13. A current surge protector cover for an electric power line, which comprises: an element for forming a first longitudinally extending chamber from a substantially continuous flexible panel; and an element for forming a second chamber extending longitudinally inside the first chamber, wherein the second longitudinally extending chamber is configured to enclose an electric power line, and wherein the second longitudinally extending chamber is longitudinally coextensive with the first chamber that extends longitudinally. 14. A current surge protection cover according to claim 13, which further comprises an element for inhibiting the electric arc from the power line to the first chamber. 15. A current surge protection cover according to claim 13, which further comprises an element for enabling the cover to be wound in a configuration not installed around a spool.